Question

我有两张桌子Table1＆amp; Table2

表1

s.no|uniqueNumber | assigned_to
1.  | S123        | Tom
2.  | S234        | Harry
3.  | S345        | Tom

表2

s.no|uniqueNumber | status
1.  | S123        | approve
2.  | S234        | approve
3.  | S345        | reject

我想抓取uniqueNumber为status＆amp; {}的approve assigned到Tom。我正在尝试将UNION与where子句一起使用。但我认为UNION在这里不起作用。怎么做到这一点？

Answer 1

您必须使用加入：

select table1.uniqueNumber, status, assigned_to
from table1
inner join table2 on table1.uniqueNumber = table2.uniqueNumber
where status = 'approve' and assigned_to ='Tom'

Answer 2

像

这样的东西

SELECT    t1.uniquenumber
FROM      table1 AS t1
JOIN      table2 AS t2
ON        t1.uniquenumber = t2.uniquenumber
WHERE     t2.status = 'approve'
AND       t1.assigned_to = 'Tom'

Answer 3

您可以使用子查询，如...

select table1.uniqueNumber from table1 where assigned_to='Tom' 
       and table1.uniqueNumber 
       in  (
             select table2.uniqueNumber from  table2 where 
             status='approve'          
            );

OR ..

你可以直接加入两个表..

select table1.uniqueNumber
       from table1 join table2 
         on table1.uniqueNumber = table2.uniqueNumber
         where status = 'approve' and assigned_to ='Tom'

如何从两个表中获取数据？

3 个答案: